In many cases it is necessary to fasten other functional parts to metal plates or metal sheets. This can basically occur by way of welding, possibly by riveting, screwing, etc.
In mobile communications as a rule a plurality of emitter devices, regardless of whether they have by way of example single or dual polarisation, are often assembled in one or more gap(s) in a fitting direction (conventionally in the vertical direction) at a spacing from each other and in front of a reflector. The reflector forms the outer skin of the antenna, wherein a radome protecting the emitters is provided on the reflector on the side which receives the emitters. In addition, a large number of functional parts must be provided on the reflector, and in particular insulating supports on which by way of example adjustment elements are movably mounted and are required to actuate phase shifters accommodated in the antenna device to set a different down-tilt angle. Furthermore, functional supports of this kind are often also used to anchor a large number of cables, and in particular coaxial cables or strip lines, etc. thereto, and these run inside the antenna (therefore as a rule in front of the reflector and underneath the radome covering the entire antenna device).
In addition to cable retainers of this kind, retainers for connecting rods, by way of example for actuation of said phase shifters, retainers for coupling elements, etc., a large number or supports are therefore used, which for the sake of simplicity will hereinafter be called functional supports for short, as are assembled by way of example on a reflector, i.e. a reflector sheet on the emitter side of the reflector.
Standard fastening means or retainers made of plastics material parts are conventionally used for this purpose and are fitted on the reflector side with a receiving space provided with undercuts, in which space by way of example a nut, in particular an aluminium nut, is non-rotatably held. The shaft of the threaded screw is then screwed from the back of the reflector into this aluminium nut, through a hole made in the reflector, until the functional part is fastened to the reflector sheet.
Since, on the other hand, the entire antenna device should be as impermeable as possible, as a rule screws are used which have a circumferential annular groove on the underside of the screw head. An O-shaped rubber-resilient sealing element is inserted in this annular groove. When the screw is tightened, the rubber-resilient element is consequently pressed between the underside of the screw head and the back of the reflector so that if possible no moisture can penetrate into the interior of the antenna housing (radome) by way of the hole in the reflector sheet through which the screw shaft penetrates.
As a rule there is an additional problem, moreover, in that the occurrence of intermodulations cannot be ruled out with fastening methods of this kind. Such intermodulations are disadvantageous in particular in high-frequency technology, however, and primarily in the field of mobile communications technology.
The object of the present invention is therefore to create an improved fastening mechanism which can preferably be applied in the case of metal sheets, as well as an associated method for its production.
With respect to a correspondingly constructed metal plate comprising a retaining and anchoring device provided according to the invention, the object is achieved according to the features disclosed in claim 1 and, with respect to a method according to the invention is achieved according to the features disclosed in claim 15.
Advantageous embodiments of the invention are disclosed in the subclaims.
The present invention takes a completely new path which has distinct advantages over the previous approach.
According to the invention, it is namely proposed that a retaining section is constructed on a metal plate, and in the present case, in particular in the field of mobile communications technology, on a reflector sheet, to which section a functional support can then be fastened.
The core of the invention is founded on the fact that the corresponding retaining section is constructed on the plate in a manner free from holes, i.e. is completely impermeable.
In a deviation from the prior art, a hole does not therefore need to be made in the sheet to introduce a screw shaft for fastening of a functional carrier. The impermeability of the support sheet is retained in full as a result.
A further fundamental advantage has proven to be that within the scope of the invention no additional part, such as a screw, a nut, etc. is necessary, as was previously required in the prior art.
The solution according to the invention is finally distinctive in that a sheet stamping, namely a sheet stamping comprising an undercut, is introduced at a specific fastening or retaining section on the metal plate to which a functional support is to be fastened.
A functional support, by way of example in the form of a plastics material part, can then be anchored in this sheet stamping comprising an undercut and configured in the manner of a recess, and this part is provided on the fastening side with a catch. This catch preferably comprises at least two snap-on fingers located in the circumferential direction or opposing each other, comprising projections protruding into the undercut, whereby the fastening part can be securely and firmly inserted and anchored on the metal plate in the region of the stamping provided with the undercut.
To prevent accidental removal or withdrawal of the functional part provided with the catch from the recess, provided with an undercut, in the form of an impression, according to one design a locking element can optionally then be attached to the functional part, and this prevents the catch finger formed in the manner of a catch and provided with projections from being withdrawn counter to the latching direction and the functional part from being able to be lifted.
The functional part itself can have a wide variety of designs, by way of example with a cross member, etc. in order to fasten cables, axially displaceable connecting rods, and decoupling elements, etc. thereon.
The stamping provided with an undercut preferably consists of a recess opposite the circumferential plate material, by way of example in a rotationally symmetrical form or in a form different to this with a different longitudinal or transverse extension. The undercut therefore does not have to be designed so as to be circumferential either and instead is preferably at offset locations that are at least different in the circumferential direction.
The stamping or impression can also be provided such that is does not protrude over the plane of the bottom of the plate, in particular if, adjacent to the stamping provided with the undercut, the remaining plate material section is relatively lowered in the opposite direction so that the corresponding retaining and anchoring section with the recessed stamping provided with the undercut protrudes above the reflector material in an elevated manner.
Finally, within the meaning of a functional reversal, a design of the retaining and anchoring section is also possible in such a way that a circumferential recessed stamping is formed which, by way of example, has undercuts which are adjacent to each other but not opposing (because by way of example an annular recess is formed in which the undercut is provided in the centrally located “island”) so that a catch with projections pointing towards each other can be attached thereto. This may be achieved by way of example in that a more annular recess is worked into the metal sheet as a stamping, wherein a circumferential or intermittent undercut is formed in the centre of the annular, ring-like or oval, etc. recessed elevation.
Basically it would also still be possible and conceivable for no shared, continuous, and in particular recessed, stamping to be formed opposite the surrounding plate material comprising a circumferential undercut, but for mutually offset stampings, single stampings comprising at least one undercut to be formed instead so that one functional part respectively comprising corresponding feet constructed in the manner of a catch can be attached so that the individual feet can engage in a stamping associated therewith in each case and can reach behind the undercut located there.